Semiconductor device having a wiring layer of damascene structure and method for manufacturing the same

ABSTRACT

In a semiconductor device, a wiring pattern groove is formed in a surface portion of a silicon oxide film provided above a semiconductor substrate. A wiring layer is buried into the wiring pattern groove with a barrier metal film interposed therebetween. The barrier metal film is selectively removed from each sidewall portion of the wiring pattern groove. In other words, the barrier metal film is left only on the bottom of the wiring pattern groove. Thus, a damascene wiring layer having a hollow section whose dielectric constant is low between each sidewall of the wiring pattern groove and each side of the wiring layer can be formed in the semiconductor device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 09/883,210,filed Jun. 19, 2001, which claims the benefit of priority from the priorJapanese Patent Application No. 2000-185152, filed Jun. 20, 2000, theentire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor device having a wiringlayer of damascene structure and a method for manufacturing thesemiconductor device. More specifically, the present invention relatesto a damascene technique that is very useful for miniaturizing asemiconductor device and decreasing the size of a chip.

Miniaturization of semiconductor devices has recently been advanced tomake a wiring layer difficult to form by conventional RIE (Reactive IonEtching). This difficulty is ascribed to difficulties in improvement ofyields and flattening when a conductive film is microfabricated by theRIE. As a technique of resolving this problem, a wiring layer ofdamascene structure (referred to as a damascene wiring layer) has beenknown conventionally.

FIGS. 9A to 9C schematically show a process of manufacturing a prior artsemiconductor device having a damascene wiring layer (a method offorming a damascene wiring layer).

First, an interlayer insulation film 101 is formed on a semiconductorsubstrate 100 and a wiring pattern groove 103 is formed in theinterlayer insulation film 101 by known lithography and RIE, as shown inFIG. 9A. Then, a barrier metal film 105 is deposited on the entiresurface of the resultant structure, as illustrated in FIG. 9B. Aconductive film 107 is deposited on the barrier metal layer 105 tocompletely fill the wiring pattern groove 103.

After that, the surface of the resultant structure is flattened by CMP(chemical mechanical polishing), as shown in FIG. 9C. A damascene wiringlayer 109 is thus obtained in which the conductive film 107 and thebarrier metal film 105 are buried into the wiring pattern groove 103.

A multilevel wiring layer can easily be formed if the above-describedprocess is repeated.

In forming a damascene wiring layer, however, it was necessary todeposit titanium nitride (TiN), niobium (Nb) and the like as a barriermetal film 105 in order to bury tungsten (W), aluminum (Al) and the likein the wiring pattern groove 103 as the conductive film 107. The barriermetal film 105 increases in adhesion to the interlayer insulation film101 of tungsten (W) and serves as a glue layer or a barrier layer inreflowing of aluminum (Al).

The resistivity of the barrier metal film 105 is generally higher thanthat of the conductive film 107. Therefore, the prior art semiconductordevice described above had a problem that the resistance of thedamascene wiring layer was higher than a wiring layer formed by the RIEmethod (referred to as an RIE wiring layer hereinafter).

FIGS. 10A and 10B illustrate a damascene wiring layer and an RIE wiringlayer having the same line width L for purposes of comparison.

In the damascene wiring layer 109 shown in FIG. 10A, the barrier metalfilm 105 is formed on each sidewall of the conductive film 107. Thus,the width L′ of the conductive film 107 is smaller than the line width Lof the damascene wiring layer 109 by two times (2b) the thickness of thebarrier metal film 105 (L′=L−2b <L). In the RIE wiring layer 201 shownin FIG. 10B, the width L′ of the conductive film 107 is equal to theline width L of the RIE wiring layer 201 (L′=L). In other words, thecross-sectional area (volume) of the conductive film 107 in thedamascene wiring layer 109 is relatively smaller than that in the RIEwiring layer 201.

The thickness (b) of the barrier metal film 105 is determinedappropriately to serve as a glue layer for forming the conductive film107, to secure adhesion enough to form the film 107, or to obtain goodcharacteristics of contact with the interlayer insulation film 101. Inshort, the barrier metal film 105 having a given thickness or more isindispensable for forming the damascene wiring layer 109.

If the damascene technique is applied to the formation of wiring, thevolume of the barrier metal film in the wiring increases relatively as asemiconductor device decreases in size. As a result, the cross-sectionalarea of the conductive film decreases and thus the resistance of thewiring increases, or a so-called thin-wire effect is problematic.

The above barrier metal film has the problems that it hardly contributesto a reduction in wiring resistance and narrows a distance betweenadjacent wiring layers and increases the capacitance between them.

The prior art damascene wiring layer has the problems that the wiringresistance increases and the wiring-to-wiring capacitance increasesthough the conductive film is improved in yield and easily flattened andthe semiconductor device can sufficiently be miniaturized.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a semiconductor devicecapable of preventing wiring resistance from increasing and preventingwiring-to-wiring capacitance from increasing and easily improving inperformance, and a method for manufacturing the semiconductor device.

In order to attain the above object, a semiconductor device according toa first aspect of the present invention comprises a first insulationfilm provided above a semiconductor substrate, a conductive filmselectively provided at least on a bottom of a groove section formed inthe first insulation film and a wiring layer formed on the conductivefilm so as to have a space region between the wiring layer and at leastone sidewall of the groove section.

A semiconductor device according to a second aspect of the presentinvention comprises a first insulation film provided above asemiconductor substrate, a wiring layer buried in the first insulationfilm, a conductive film provided at least on a bottom of the wiringlayer, and a fourth insulation film formed on at least one side of thewiring layer, the fourth insulation film being different from the firstinsulation film.

A semiconductor device according to a third aspect of the presentinvention comprises an insulation film provided above a semiconductorsubstrate, a wiring layer buried in the insulation film, a firstconductive film provided at least on a bottom of the wiring layer, and asecond conductive film formed on at least one side of the wiring layer.

A semiconductor device according to a fourth aspect of the presentinvention comprises a first insulation film provided above asemiconductor substrate, at least two wiring layers buried in the firstinsulation film, a first conductive film provided on a bottom of each ofthe wiring layers, a fifth insulation film formed on at least one sideof each of the wiring layers, and a contact plug provided between thetwo wiring layers with the fifth insulation film interposedtherebetween.

A method of manufacturing a semiconductor device according to a fifthaspect of the present invention, comprises the steps of forming a groovesection in a first insulation film provided above a semiconductorsubstrate, forming a first conductive film on the first insulation filmalong the groove section, forming a buried wiring layer in the groovesection with the first conductive film interposed therebetween, andselectively removing the first conductive film from at least onesidewall portion of the groove section to form a space region betweenthe sidewall portion and one side of the wiring layer.

A method of manufacturing a semiconductor device according to a sixthaspect of the present invention, comprises the steps of forming a groovesection in a first insulation film provided above a semiconductorsubstrate, forming a third insulation film on at least one sidewallportion of the groove section, forming a first conductive film in thegroove section along the third insulation film, forming a buried wiringlayer in the groove section with the first conductive film interposedtherebetween, and selectively removing the third insulation film from atleast one sidewall portion of the groove section to form a space regionbetween the sidewall portion and one side of the wiring layer.

A method of manufacturing a semiconductor device according to a seventhaspect of the present invention, comprises the steps of forming at leasttwo groove sections in a first insulation film provided above asemiconductor substrate, forming a first conductive film on the firstinsulation film along each of the two groove sections, forming a buriedwiring layer in each of the two groove section with the first conductivefilm interposed therebetween, selectively removing the first conductivefilm from at least one sidewall portion of each of the two groovesection, and forming a contact plug between the two groove sections witha fifth insulation film interposed therebetween.

According to the semiconductor device and the method for manufacturingthe same described above, the sidewall portions of a groove section caneffectively be used. Thus, the wiring resistance can easily be decreasedand so can be the wiring-to-wiring capacitance.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a cross-sectional view showing a main portion of asemiconductor device having a damascene wiring layer according to afirst embodiment of the present invention;

FIGS. 2A to 2F are cross-sectional views showing a process of formingthe damascene wiring layer of the semiconductor device according to thefirst embodiment of the present invention;

FIGS. 3A to 3C are cross-sectional views showing a process ofmanufacturing a semiconductor device having a damascene wiring layer (amethod of forming a damascene wiring layer) according to a secondembodiment of the present invention;

FIGS. 4A to 4C are cross-sectional views showing a process ofmanufacturing a semiconductor device having a damascene wiring layer (amethod of forming a damascene wiring layer) according to a thirdembodiment of the present invention;

FIGS. 5A to 5G are cross-sectional views showing a process ofmanufacturing a semiconductor device having a damascene wiring layer (amethod of forming a damascene wiring layer) according to a fourthembodiment of the present invention;

FIGS. 6A to 6E are cross-sectional views showing a process ofmanufacturing a semiconductor device having a damascene wiring layer (amethod of forming a damascene wiring layer) according to a fifthembodiment of the present invention;

FIGS. 7A to 7F are cross-sectional views showing a process ofmanufacturing an example of a semiconductor device according to a sixthembodiment of the present invention, which is applied to a DRAM cellusing a stacked capacitor;

FIG. 8 is a cross-sectional view showing another example of thesemiconductor device according to the sixth embodiment of the presentinvention;

FIGS. 9A to 9C are cross-sectional views showing a process ofmanufacturing a semiconductor device having a damascene wiring layer (amethod of forming a damascene wiring layer) in order to describe a priorart technique and its problems; and

FIGS. 10A and 10B are cross-sectional views showing a damascene wiringlayer and an RIE wiring layer having the same line width in the priorart technique for purposes of comparison.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will now be described withreference to the accompanying drawings.

FIRST EMBODIMENT

FIG. 1 schematically shows a cross section of a semiconductor devicehaving a damascene wiring layer according to a first embodiment of thepresent invention.

In FIG. 1, a silicon oxide film (insulation film/first insulation film)12 is provided directly or indirectly on a semiconductor substrate 11. Awiring pattern groove (groove section) 13 is formed in a surface portionof the silicon oxide film 12. A barrier metal film (conductivefilm/first conductive film) 14 is selectively formed only on the bottomof the groove 13. A wiring layer 16, which is constituted of aconductive film, is provided on the barrier metal film 14. A hollowsection (space region) 15 is formed between each sidewall of the groove13 and each side of the wiring layer 16. The wiring layer 16 is almostflush with the groove 13. A plasma SiO₂ film (second insulation film) 17is formed on the entire surface of the silicon oxide film 12.

The hollow section 15 is obtained by selectively removing a barriermetal film formed on each sidewall of the groove 13.

The above structure results in a damascene wiring layer with a hollowsection of low dielectric constant on its sides. Even when a damascenetechnique is used for forming a wiring layer, the wiring-to-wiringcapacitance can be reduced effectively maintaining a high yield.

A method of forming a damascene wiring layer with the above structurewill now be described with reference to FIGS. 2A to 2F.

First, as shown in FIG. 2A, a silicon oxide film 12 is formed directlyor indirectly on a semiconductor substrate 11. A wiring pattern groove13 is formed in a surface portion of the silicon oxide film 12 by knownlithography and RIE.

Then, as shown in FIG. 2B, a TiN film 14′ serving as a barrier metalfilm 14 is deposited on the entire surface of the resultant structure toa given thickness. The TiN film 14′ is formed by CVD (Chemical VaporDeposition) using an organic raw-material gas.

Referring to FIG. 2C, only the quality of the TiN film 14 a′ exposed toat least the bottom of the groove 13 is changed by anisotropic plasmaprocessing.

The just-deposited TiN film contains a large number of organicimpurities such as carbon. The TiN film is low in density and veryunstable. Therefore, the TiN film should be changed to a dense one byscattering the impurities by plasma processing.

Since the plasma processing is anisotropic, the TiN film 14 b formed onthe sidewalls of the groove 13 is hardly exposed to plasma. The TiN film14 b′ remains unstable to cause a difference in quality between the TiNfilm 14 b′ and the TiN film 14 a′ formed on the bottom of the wiringpattern groove 13.

As FIG. 2D illustrates, a conductive film (e.g., W) 16′, which is toserve as a wiring layer 16, is deposited on the entire surface of theresultant structure by CVD to completely fill the groove 13.

As FIG. 2E illustrates, a wiring layer 16 is formed by flattening thesurface of the resultant structure by CMP. In this case, the conductivefilm 16′ and TiN film 14′ are selectively removed until the top surfaceof the silicon oxide film 12 is exposed and, in other words, they areselectively removed from the silicon oxide film 12 but not from insidethe groove 13.

Referring to FIG. 2F, the TiN film 14 b′ is selectively removed from thesidewalls of the groove 13 by diluted-SH (e.g., 10% H₂SO₄:35% H₂O₂=22litter: 9 ml, 80□, several tens of minutes) processing. The barriermetal film 14 is thus formed only from the TiN film 14 a′ on the bottomof the wiring pattern groove 13. Since the TiN film 14 b′ on thesidewalls of the groove 13 remains unstable, the rate of wet etching ishigh and the TiN film 14 a′ can selectively be removed from the bottomof the groove 13 and the wiring layer 16.

After that, a plasma SiO₂ film 17 is deposited on the entire surface ofthe resultant structure by plasma CVD. A hollow section 15 is formedbetween each side of the wiring layer 16 and each sidewall of the groove13. Thus, a semiconductor device having a damascene wiring layer asshown in FIG. 1 can be obtained.

In the first embodiment, poor burying (coverage) characteristics of theplasma SiO₂ film 17 prevent the film 17 from being buried into anetching region 15 a excluding the TiN film 14 b′. Consequently, thehollow section 15, which is capable of effectively reducing thewiring-to-wiring capacitance, can be formed easily.

SECOND EMBODIMENT

In the above first embodiment, the etching region 15 a from which theTiN film 14′ is partly removed using the plasma SiO₂ film 17 thecoverage characteristics of which are poor, is used effectively as thehollow section 15. The present invention is not limited to this feature.For example, the etching region 15 a can be filled with an insulationfilm (fourth insulation film) 21, as illustrated in FIGS. 3A to 3C.

After the step shown in FIG. 3A which is the same as that shown in FIG.2F of the first embodiment, an insulation film 21 whose buryingcharacteristics are improved is deposited on the entire surface of theresultant structure in place of the plasma SiO₂ film 17, as illustratedin FIG. 3B. By flattening the insulation film 21 by CMP as shown in FIG.3C, it is left only in the etching region 15 a. For example, a TEOS(Tetraethyl Orthosilicate) film formed by plasma CVD or an SOG (Spin OnGlass) film formed by coating is used as the insulation film 21.

In the second embodiment, when a damascene wiring layer is formed, theside portions of a wiring layer 16 can be used as insulation regions bysubstituting the insulation film 21 for regions (sidewalls of wiringpattern groove 13) in which the barrier metal film 14 is originallyprovided. If, therefore, the wiring pattern groove 13 is widened inadvance by the thickness of the barrier metal film 14, an increase inwiring resistance due to microfabrication can be suppressed effectively.

THIRD EMBODIMENT

FIGS. 4A to 4C schematically show a process of manufacturing asemiconductor device having a damascene wiring layer (a method offorming a damascene wiring layer) according to a third embodiment of thepresent invention. In the third embodiment, the process up to the stepof selectively removing the TiN film 14 b′ from the sidewalls of thewiring pattern groove 13 is the same as that shown in FIGS. 2A to 2F ofthe first embodiment. The steps subsequent thereto will now be describedbelow.

The TiN film 14 b′ is selectively removed from the sidewalls of thegroove 13 by SC-2 processing to form a barrier metal film 14 (see FIG.4A). Then, a W film (second conductive film) 31 is deposited on theentire surface of the resultant structure by sputtering or CVD, as shownin FIG. 4B.

As FIG. 4C illustrates, the resultant structure is flattened by CMP andthe W film 31 is removed until the top surface of a silicon oxide film12 is exposed.

Thus, an etching region 15 a between each side of the wiring layer 16and each sidewall of the groove 13 is completely filled with the W film31.

In the third embodiment, too, the side portions of the wiring layer 16can be used as wiring regions by substituting the W film 31 for regions(sidewalls of the groove 13) in which the barrier metal film 14 isoriginally provided. The line width of a damascene wiring layer can thusbe increased by the thickness of the barrier metal film 14. In otherwords, the region corresponding to the thickness of the barrier metalfilm 14 can be used as a wiring layer without waste. A semiconductordevice with the above damascene wiring layer can be microfacbricatedwithout increasing the resistance of wiring.

Not only the W film but also any other conductive film can be used asthe second conductive film that is buried into the etching region 15 a.

FOURTH EMBODIMENT

In the first to third embodiments, a spacer (third insulation film) canbe provided on each sidewall of the wiring pattern groove 13.

FIGS. 5A to 5G schematically show a process of manufacturing asemiconductor device having a damascene wiring layer (a method offorming a damascene wiring layer) according to a fourth embodiment ofthe present invention. The fourth embodiment will now be described inbrief, taking the first embodiment in which the hollow section 15 isprovided between each sidewall of the wiring pattern groove 13 and eachside of the wiring layer 16 as an example.

A silicon oxide film 12 is formed directly or indirectly on asemiconductor substrate 11. A wiring pattern groove 13 is formed in asurface portion of the silicon oxide film 12 by known lithography andRIE. After that, a SiN (silicon nitride) film serving as a thirdinsulation film is deposited on the surface of the silicon oxide film 12by CVD. Then, the SiN film is selectively removed by anisotropic etchingand left only on each sidewall of the groove 13, thereby forming aspacer 41 (see FIG. 5A).

If the same steps as those of FIGS. 2B et seq. are executed after theabove step, a semiconductor device having a damascene wiring layer canbe obtained in which the spacer 41 is provided on each sidewall of thegroove 13 and the hollow section 15 is formed between the spacer 41 andeach side of the wiring layer 16.

The structure of the fourth embodiment can produce an advantage as wellas that of the first embodiment. Not only wiring-to-wiring capacitancecan effectively be reduced maintaining a high yield, but alsowiring-to-wiring insulating characteristics can be improved further. Thesemiconductor device can thus be microfabricated more greatly.

In the fourth embodiment, too, an insulation film 21, a W film or thelike can easily be buried into the etching region 15 a in place of thehollow section 15, as in the second and third embodiments describedabove.

FIFTH EMBODIMENT

FIGS. 6A to 6E schematically show a process of manufacturing asemiconductor device having a damascene wiring layer (a method offorming a damascene wiring layer) according to a fifth embodiment of thepresent invention.

The fifth embodiment is directed to a case where a hollow section 15 isformed by removing the spacer 41, which is formed on each sidewall ofthe wiring pattern groove 13 in the fourth embodiment.

Referring first to FIG. 6A, a silicon oxide film 12 is formed directlyor indirectly on a semiconductor substrate 11 and a wiring patterngroove 13 is formed in a surface portion of the silicon oxide film 12 byknown lithography and RIE.

After that, as shown in FIG. 6B, a SiN film serving as a thirdinsulation film is deposited on the surface of the silicon oxide film 12by CVD. The SiN film is selectively removed by anisotropic etching andleft only on each sidewall of the groove 13, resulting in spacers 41.

A TiN film serving as a barrier metal film 14 is deposited on the entiresurface of the resultant structure and a W film serving as a wiringlayer 16 is deposited thereon. As FIG. 6C illustrates, the resultantstructure is flattened by CMP until the top surface of the silicon oxidefilm 12 is exposed, resulting in the barrier metal film 14 and the wringlayer 16.

Wet etching in phosphoric acid allows the spacers 41 to be selectivelyremoved from the sidewalls of the groove 13, as shown in FIG. 6D.

Referring to FIG. 6E, a plasma SiO₂ film 17 is deposited on the entiresurface of the resultant structure by plasma CVD. The film 17 inhibitsthe etching region 15 a excluding the spacers 41 from being filledcompletely. Consequently, a semiconductor device having a damascenewiring layer can be manufactured in which a hollow section 15 isprovided along each sidewall of the groove 13.

The etching region 15 a is therefore prevented from being filledcompletely using a film of poor coverage characteristics such as plasmaSiO₂ on purpose. As in the first embodiment, the hollow section 15 caneasily be formed along each sidewall of the wiring pattern groove 13excluding the spacers 41. The section 15 allows the wiring-to-wiringcapacitance to be reduced effectively.

According to the fifth embodiment, the hollow section 15 can be formedalong each side of the wiring layer 16 with good controllability evenwhen the barrier metal film 14 is difficult to selectively remove fromthe wiring layer 16 or even though no anisotropic plasma processing isexecuted.

SIXTH EMBODIMENT

FIGS. 7A to 7E schematically show a process of manufacturing asemiconductor device having a damascene wiring layer (a method offorming a damascene wiring layer) according to a sixth embodiment of thepresent invention. The sixth embodiment is directed to a DRAM cell usinga stacked capacitor. In the sixth embodiment, the process up to the stepof forming the wiring layer 16 is the same as that shown in FIGS. 2A to2E of the first embodiment. The steps subsequent thereto will now bedescribed below.

After the wiring layer 16 is formed by executing the same steps as thoseof FIGS. 2A to 2E (see FIG. 7A), it is selectively removed by RIE usingCl₂ gas.

Thus, a bit line 51 is formed lower than the top surface of the siliconoxide film 12 (see FIG. 7B).

As in the first embodiment, a TiN film 14 b′ is selectively removed fromeach sidewall of the wiring pattern groove 13 by SC-2 processing. Thus,a barrier metal film 14 is formed from only the TiN film 14 a′ on thebottom of the groove 13 (see FIG. 7C).

A silicon nitride film 52 is deposited on the entire surface of theresultant structure by CVD. An etching region 15 a excluding the TiNfilm 14 b′ and a step region 15 b formed by etching the wiring layer 16are completely filled with the silicon nitride film 52. Then, the film52 is flattened by CMP such that it is flush with the top surface of thesilicon oxide film 12, thus forming a sidewall (fifth insulation film)53 in the etching region 15 a (see FIG. 7D).

A photoresist film (not shown) is formed on the silicon oxide film 12and patterned by known lithography. The photoresist film and siliconnitride film 52 are removed by RIE using C₄F₈ gas having a highselection ratio. The silicon oxide film 12 is selectively etched to forma contact hole 54 reaching the semiconductor substrate 11. The contacthole 54 is formed in self-alignment with the silicon nitride film 52(see FIG. 7E).

After the photoresist film is eliminated, a TiN film serving as abarrier metal film (third conductive film) 55 and a conductive film(e.g., tungsten) serving as a storage node contact (fourth conductivefilm) 56 are deposited on the entire surface of the resultant structureby CVD to fill the contact hole 54 completely. By flattening thestructure by CMP until the top surface of the silicon oxide film 12 isexposed, a contact plug is formed of the barrier metal film 55 and thestorage node contact 56 (see FIG. 7F).

After that, a capacitor and a plate electrode are formed in the samemanner as those of the normal DRAM cell.

According to the sixth embodiment, the storage node contact 56 can beformed in self-alignment with the bit line 51 in a DRAM cell using astacked capacitor. No margin for alignment is required for forming thecontact hole 54. Therefore, a distance between bit lines 51 cansufficiently be reduced and the chip size can easily be decreased.

In particular, sidewalls 53 for insulating the bit lines 51 and thestorage contact 56 from each other are formed at the same time when thesilicon nitride film 52 is buried into the step region 15 b. The numberof manufacturing steps can thus be reduced. Moreover, the regions (sideportions of the bit lines 51) that correspond to those occupied by thebarrier metal film can effectively be used as the sidewalls 53.Consequently, a so-called thinning effect of increasing the resistanceof the bit lines 51 can easily be suppressed.

In the embodiment described above, the step region 15 b (bit line 51) isformed by selectively etching the wiring layer 16 and then the TiN film14 b′ is removed from each sidewall of the wiring pattern groove 13. Thepresent invention is not limited to this structure. For example, the bitline 51 can easily be formed after the TiN film 14 b′ is selectivelyremoved.

If the present invention is applied to the DRAM cell using a stackedcapacitor, a spacer (fifth insulation film) 41′ can be provided at leastbetween the wiring pattern groove 13 and the contact hole 54, asillustrated in FIG. 8. In this case, a hollow section 15 can be formedbetween the bit line 51 and the spacer 41′ as in the fourth embodiment(see FIGS. 5A to 5G). The capacitance between the bit line 51 and thestorage node contact 56 can effectively be reduced.

As described above, the sidewalls of the wiring pattern groove caneffectively be utilized. In other words, a hollow section is formed, aninsulation is buried, or a conductive film is buried between eachsidewall of the wiring pattern groove and each side of the wiring layerin the damascene wiring layer. When the hollow section is formed, thewiring-to-wiring capacitance can be prevented from increasing. When theinsulation film is buried, the wiring-to-wiring insulationcharacteristics can be improved. When the conductive film is buried, anincrease in wiring resistance due to the thinning effect can beprevented. This is very effective in miniaturizing a semiconductordevice and decreasing the size of a chip. The suppression of thethinning effect effectively allows the wiring resistance to decrease andallows the wiring-to-wiring capacitance to reduce, with the result thatthe semiconductor device can easily be improved in performance.

In the foregoing embodiments of the present invention, a hollow sectionis provided along each sidewall of the wiring pattern groove. Thepresent invention is not limited to this structure. The hollow sectioncan be provided only on the sidewall adjacent to at least anotherdamascene wiring layer.

According to the present invention described above, there can beprovided a semiconductor device capable of preventing a wiringresistance and a wiring-to-wiring capacitance from increasing and easilyimproving in performance and a method of manufacturing the semiconductordevice.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A semiconductor device comprising: a first insulation film providedabove a semiconductor substrate; a conductive film selectively providedat least on a bottom of a groove section formed in the first insulationfilm; and a wiring layer formed on the conductive film so as to have aspace region between the wiring layer and at least one sidewall of thegroove section; a second insulation film formed above the space region,the second insulation film being different from the first insulationfilm; and a third insulation film formed on a sidewall of the groovesection, the third insulation being different from the first and secondinsulation films.
 2. A semiconductor device comprising: a firstinsulation film provided above a semiconductor substrate; a wiring layerburied in the first insulation film; a conductive film provided at leaston a bottom of the wiring layer; and a fourth insulation film formed onat least one side of the wiring layer, the fourth insulation film beingdifferent from the first insulation film.
 3. The semiconductor deviceaccording to claim 2, wherein the conductive film is barrier metal andhas resistivity that is higher than that of the wiring layer.
 4. Asemiconductor device comprising: an insulation film provided above asemiconductor substrate; a wiring layer buried in the insulation film; afirst conductive film provided at least on a bottom of the wiring layer;and a second conductive film formed on at least one side of the wiringlayer.
 5. The semiconductor device according to claim 4, wherein thefirst conductive film is barrier metal and has resistivity that ishigher than that of the wiring layer.
 6. The semiconductor deviceaccording to claim 4, wherein the second conductive film has resistivitythat is almost equal to that of the wiring layer.
 7. A semiconductordevice comprising: a first insulation film provided above asemiconductor substrate; at least two wiring layers buried in the firstinsulation film; a first conductive film provided on a bottom of each ofthe wiring layers; a fifth insulation film formed on at least one sideof each of the wiring layers; and a contact plug provided between thetwo wiring layers with the fifth insulation film interposedtherebetween.
 8. The semiconductor device according to claim 7, whereinthe first conductive film is barrier metal and has resistivity that ishigher than that of the two wiring layers.
 9. The semiconductor deviceaccording to claim 7, wherein the two wiring layers are bit lines. 10.The semiconductor device according to claim 7, wherein the contact plugis formed in self-alignment with the fifth insulation film.
 11. Thesemiconductor device according to claim 7, wherein the contact plugincludes barrier metal of a third conductive film and a storage nodecontact of a fourth conductive film.
 12. The semiconductor deviceaccording to claim 7, wherein a space region is provided between atleast one side of each of the two wiring layers and the fifth insulationfilm.